Bug 33845: Disable Namecoin on nightly temporarily

Namecoin support is temporarily disabled, until
projects/firefox/namecoin-torbutton.patch is rebased.

rbm.conf

@@ -299,7 +299,8 @@ targets:
       # channels for now.
       snowflake: '[% c("var/alpha") || c("var/nightly") %]'
       # Only build Namecoin for linux on nightly
-      namecoin: '[% c("var/nightly") %]'
+      # Namecoin is temporarily disabled on nightly until #33845 is fixed.
+      namecoin: 0
       container:
         suite: wheezy
         arch: amd64